Specimens such as but not limited to wafers may be reviewed using a scanning electron microscope. A scanning electron microscope (SEM) must maintain a very low vacuum level within a specimen chamber in order to provide high resolution SEM images.
Wafers can be entered to the specimen chamber of the SEM only after they are dry enough—their outgassing level is below a predefined outgassing level.
Wafers may be positioned within an exchange chamber before entering the specimen chamber of the SEM. After receiving the wafer the exchange chamber is sealed and the exchange chamber starts to constantly evacuate gas within the exchange chamber—until the exchange chamber pressure reaches a low enough level.
An exchange chamber pressure monitor is used for preforming exchange chamber pressure measurements in order to evaluate the outgassing of the wafer within the exchange chamber.
The constant evacuation may speed up the provision of the wafer to the SEM but introduces noise and otherwise deteriorates the accuracy of exchange chamber pressure measurements.
There is a growing need to provide a system and method for accurately estimating the outgassing of a specimen (such as a wafer) within an exchange chamber.